Spacecraft often include various radio-frequency (RF) systems that are used to communicate with remote objects, e.g., other satellites or ground-based antennas. These RF systems may operate in a number of radio-frequency bands, including the Ku band, which is typically used for satellite communications, terrestrial microwave communications, and radar systems. In some newer satellite systems, RF systems that operate in the Ka band are being used or are being contemplated for use.
One particular component that may be used in satellite RF systems is a cavity filter, which generally consists of a filled or unfilled (loaded or unloaded) resonator cavity. Some resonator cavities may include a dielectric resonator located within the cavity. The cavity filter generally permits RF energy of certain frequencies to pass, while rejecting RF energy of other frequencies. Such filters are described, for example in U.S. Pat. No. 6,297,715, assigned to the assignee of the present invention, and hereby incorporated into the present application in its entirety. Other examples of known resonator cavity filters are described in U.S. Pat. Nos. 8,952,769 and 9,019,039, assigned to the assignee of the present invention, and hereby incorporated in their entireties into the present application.
The RF energy that is lost during the filtering process is converted into heat energy that must then be dissipated by the filter system. This can prove to be quite challenging in a vacuum environment, such as is experienced in satellites, as cooling strategies involving convection are not effective.